Is it a bad thing if... (1 Viewer)

airon23

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...the thermostat takes forever to "warm up"? Seems like my 76 FJ40 with 2F rebuild takes a long time before really warming up anything significant. Before the gasket engine refresh I did last summer it had the same thing happening, takes forever to really heat up. Almost to the point you think the gauge doesn't work because it stays on C the whole time. If I'm driving around at higher speeds it will eventually start to creep up a little ways away from C but not even half way to H on the gauge.

Heater is what prompted me to ask this question. When refreshing the motor, I also installed a Vintage Air AC/Heater unit. So winter weather I try turning on the heater but doesn't really blow much heat if any. To be fair it had the same problem before but I don't take it out too often.
Of other note, I never charged the AC unit with R134 because winter was coming and I figured I didn't need to do that, but I don't think that would effect anything.

Thoughts?
 

airon23

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It's brand new. Not that it isn't possible. @65swb45 had seen my last one a year or 2 ago when it wouldn't warm up and he hypothesized there was no thermostat which proved to be wrong once I opened it up. So I ordered a new one from him hoping if the other was bad this would fix the "issue". Again, I don't know how much of an issue it is other than I don't get heat in the cab.
 
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It's brand new. Not that it isn't possible. @65swb45 had seen my last one a year or 2 ago when it wouldn't warm up and he hypothesized there was no thermostat which proved to be wrong once I opened it up. So I ordered a new one from him hoping if the other was bad this would fix the "issue". Again, I don't know how much of an issue it is other than I don't get heat in the cab.
When cold open radd cap and see if you have coolant flow, should only be flow when thermostat is open once engine gets to temp so usually a good sign of a bad one.
 
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It's brand new. Not that it isn't possible. @65swb45 had seen my last one a year or 2 ago when it wouldn't warm up and he hypothesized there was no thermostat which proved to be wrong once I opened it up. So I ordered a new one from him hoping if the other was bad this would fix the "issue". Again, I don't know how much of an issue it is other than I don't get heat in the cab.
Also, motor will run far less efficient at the lower temperature
 
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One thing I noticed when I had my 1F on the stand is how heavy these are; there is a ton of metal in the block. It could just be that your cooling system is working well and it takes a long time to heat all that cast iron and that’s the nature of it?
Also, how long is a long time and do you have stock or aluminum radiator? In my Chevelle with a really built up big block (that are a pain to cool), it takes about 10 miles of driving before I notice any heat out of the heater. In that I have an aluminum radiator and slightly lower temp thermostat with massive clutch fan to help avoid cooling issues.
 

airon23

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One thing I noticed when I had my 1F on the stand is how heavy these are; there is a ton of metal in the block. It could just be that your cooling system is working well and it takes a long time to heat all that cast iron and that’s the nature of it?
Also, how long is a long time and do you have stock or aluminum radiator? In my Chevelle with a really built up big block (that are a pain to cool), it takes about 10 miles of driving before I notice any heat out of the heater. In that I have an aluminum radiator and slightly lower temp thermostat with massive clutch fan to help avoid cooling issues.
Radiator is stock but did just have the cores replaced, although it was working pretty well before hand.

That's sort of what I'm thinking, it really just takes this long to heat, but idk. I'm talking about more than 10 miles, probably more like 15-20 and even then the heat coming from the heater isn't hot just sort of warm.
 

rkymtnflyfisher

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Halfway on my OEM gauge=overheated engine.

My needle usually hangs around 1/4 the way up from the left, that equates to approximately 180F.
 
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My OEM gauge takes forever to reach where it usually rides, around or a little above the first mark.
I figured like the guy above the heavy cast iron blocks take a while
 

rkymtnflyfisher

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I thought of this too. But wouldn't my heater be getting hot if it was just the sender was not sending the right temperature?
Heater would only be getting hot if there is flow of hot coolant through the core, so if it is clogged at all that will ruin that.
 
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Do you have BOTH gaskets on the thermostat? The one that goes on TOP of the thermostat is designed to prevent water getting around the thermostat. It takes a long time to heat up without the upper rubber seal.
 
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I never really notice much on my 40 because i mostly drive it in summers but my winter beater toyota pickup didn't heat up well until i switched over to clutch fan.
 
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Get an IR temp gauge and read the temperature of your engine head, t-stat housing, hoses to and from the heater (with the fan on high) and possibly the heater core. This will tell you a lot about your heat situation. Be sure to use the IR temp gun correctly - they don't like moving air from engine fans, so you may need to turn off the engine to get an accurate reading.
 

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